The Lab Upgrade That Slowed Down
Sunrise Public School has a 12-station computer lab used for two different jobs: senior students edit 1080p video for the annual magazine about 6 hours per week, and juniors practise spreadsheets and typing about 20 hours per week. The lab has 12 identical desktop PCs: Intel Core i3-8100, 8 GB DDR4 RAM in a single stick, 1 TB 5400 rpm HDD, integrated graphics, and a 450 W power supply. The school receives a donation of Rs 1,20,000 and a vendor offers three upgrade kits: Kit A - one 8 GB RAM stick at Rs 18,000; Kit B - one 500 GB SATA SSD at Rs 6,000; Kit C - a 4 GB graphics card at Rs 40,000 plus a required 550 W PSU at Rs 8,000. Teachers complain that Windows takes 3-4 minutes to boot, video preview stutters, and spreadsheet files open slowly from the network drive. The principal wants 'the biggest visible improvement in one month' and can upgrade only 6 machines now. The lab's switch is 100 Mbps and the file server is on the same switch.
1. Rank the three symptoms - slow boot, stuttering video preview, slow opening of network spreadsheets - by their most likely hardware or network cause. Justify each ranking and say which symptom would improve least from a CPU upgrade.
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Slow boot is most likely dominated by the 5400 rpm HDD. Windows and applications perform many small random reads during startup, and a mechanical disk has high seek and latency compared with an SSD. RAM pressure can add to this, but 8 GB is usually enough for booting.
Stuttering video preview is most likely caused by the integrated graphics sharing system RAM and by single-channel memory. The iGPU has no dedicated VRAM, so one 8 GB stick halves memory bandwidth compared with two matched sticks. The Core i3-8100 is not the main limit for preview.
Slow opening of network spreadsheets is most likely the 100 Mbps switch and the server's disk, not the desktop CPU. A 100 Mbps link is about 12.5 MB/s at best, and a large spreadsheet plus other traffic can saturate it. Local HDD caching also slows the first open. A CPU upgrade would help least overall because none of the three symptoms is primarily CPU-bound; I/O and memory bandwidth dominate.
2. Allocate the Rs 1,20,000 across the 6 machines. State exact quantities and cost, and explain why you reject the graphics-card kit for this round.
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A strong allocation is 6 SSDs (Kit B) and 4 RAM sticks (Kit A): 6 x Rs 6,000 = Rs 36,000; 4 x Rs 18,000 = Rs 72,000; total Rs 1,08,000. That leaves Rs 12,000, which is not enough for another Rs 18,000 RAM stick or for the graphics kit. All 6 upgraded machines get faster boot and application loading, and 4 get dual-channel 16 GB, which also helps integrated video preview. The other 2 machines keep 8 GB single-channel for now.
The graphics kit costs Rs 48,000 for one machine (card plus PSU). It would improve only one of the six stations, while the video class uses several machines and would queue for that one. It also introduces a PSU replacement and Physical clearance risk for a modest 4 GB card. Spending the same money on SSDs and RAM gives a visible improvement across all six machines, which matches the principal's one-month goal.
3. A parent offers a spare 650 W PSU. A teacher proposes installing the 4 GB graphics card in one machine with the existing 450 W PSU 'because 450 is close to 550'. Explain the risks and list three checks before installing the card with the 650 W PSU.
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Wattage alone is not a compatibility check. A 450 W supply may have a weak 12 V rail, no 6-pin PCIe connector, and little headroom for the card's transient power spikes. The system can shut down under load, corrupt work, or stress the PSU. The card's recommended 550 W assumes a complete system, so 'close to 550' is not a safe margin, especially with an older or unbranded unit.
Before using the 650 W PSU, check: (1) the 12 V rail current rating and total 12 V wattage against the CPU, GPU, drives, and fans; (2) the presence of the required 6-pin PCIe connector and correct pin type; (3) physical clearance in the case, motherboard PCIe x16 slot, and cooling airflow. Also confirm the PSU is not damaged and has the right input voltage. After installation, test under load and monitor temperatures and shutdowns.